Regulated Assembly of Subcellular Structures in alpha-Proteobacteria

描述(申请人提供)：细菌细胞进化出多种调节机制，以确保它们的亚细胞结构和细胞器，如菌毛和鞭毛，被正确组装和定位。我们的目标是确定一个保守的监管系统的核心组成部分及其相互作用是如何适应不同生物体的特殊需求的。在新月藻中，这种调控系统的蛋白质组分(PodJ、DivJ和Plec)遵循特定的亚细胞定位模式，这有助于不对称的细胞形态：细胞器在一极特异地发育，而在另一极不发育。调控成分在苜蓿中华根瘤菌中是保守的，它是一种在共生过程中诱导植物根瘤形成的相关细菌。然而，与新月浑草相比，紫花苜蓿细胞在形态上是对称的。我们将研究这些保守成分如何在苜蓿链霉菌中调节表面细胞器的组装，以及这种调节如何影响宿主与微生物的相互作用。(1)我们将首先确定调控蛋白的定位模式和缺失这些蛋白的零突变体的表型。(2)然后，我们将检测和分析突变体转录图谱的变化，看看这些蛋白质是否控制着相似基因在不同物种中的表达。(3)我们还将评估这些突变是否扰乱了细菌与宿主之间的相互作用，从而阻止了有效的结瘤。除了这些研究目标外，首席研究员还致力于在一名资深科学家的指导下实现以下发展目标：(4)建立独立的研究小组，(5)增强指导技能，(6)提高研究质量。 与公共卫生的相关性：这项拟议的研究有望揭示存在于包括病原体在内的多种细菌物种中的调控途径的驱动原理。该途径的组成部分可能成为新的抗菌化合物的靶点。

DESCRIPTION (provided by applicant): Bacterial cells have evolved multiple regulatory mechanisms to ensure that their subcellular structures and organelles, such as pili and flagella, are assembled and positioned correctly. Our goal is to determine how the core components of a conserved regulatory system, and their interactions, have been adapted to serve the particular needs of different organisms. In Caulobacter crescentus, the protein components of this regulatory system (PodJ, DivJ, and PleC) follow defined patterns of subcellular localization that contribute to asymmetric cell morphology: organelles specifically develop at one pole but not the other. The regulatory components are conserved in Sinorhizobium meliloti, a related bacterium that induces nodule formation in plant roots during symbiosis. However, S. meliloti cells are morphologically symmetric compared to C. crescentus. We will examine how these conserved components function in S. meliloti to regulate the assembly of surface organelles and how this regulation affects host-microbe interaction. (1) We will first determine the localization patterns of the regulatory proteins and the phenotypes of null mutants that lack the proteins. (2) We will then detect and analyze changes in the mutants' transcriptional profiles to see if the proteins control expression of similar genes in different species. (3) We will also assess whether the mutations disrupt interaction between the bacterium and its hosts, preventing effective nodulation. In addition to these research objectives, the principal investigator aims to achieve the following developmental objectives under the guidance of a senior scientist: (4) establish an independent research group, (5) enhance mentoring skills, and (6) improve the quality of research. Relevance to Public Health: The proposed research is expected to reveal the driving principles of a regulatory pathway that exists in multiple bacterial species, including pathogens. Components of the pathway may serve as targets for new antimicrobial compounds.